Apparatus for feeding paper stock to a paper machine

ABSTRACT

AN APARATUS FOR FEEDING PAPER STOCK TO A PAPER MACHINE IN WHICH EVEN DISTRIBUTION OF THE PULP STOCK FREE FROM FIBER ACCUMULATIONS IS OBTAINED ACROSS THE ENTIRE WIDTH OF THE PAPER MACHINE. THE STOCK FLOWS FROM DISTRIBUTION TUBES INTO A CHAMBER THROUGH A PLURALITY OF TRANSVERSE INLET ROWS AND IMPINGES ON THE OPPOSITE WALL OF THE CHAMBER. THE INLET WALL IS PROVIDED WITH HUMPS WHICH EXTEND ACRODD THE CHAMBER, BOTH PARALLEL TO AND BETWEEN EACH PAIR OF INLET ROWS. THE STOCK FLOWS FROM THE CHAMBER THROUGH A DISCHARGE CHANNEL AND TO THE HEAD BOX OF THE PAPER MACHINE.

July 6, 1971 NYKOPP 3,591,452

APPARATUS FOR FEEDING PAPER STOCK TO A PAPER MACHINE Filed Jan. 17, 1969 2 Sheets-Sheet 1 APPARATUS FOR FEEDING PAPER STOCK TO A PAPER MACHINE Filed Jan. 17, 1969 E. A. NYKOPP July 6, 1971 2 Sheets-Sheet 73 Fig.2

United States Patent Ofiice 3,591,452 APPARATUS FOR FEEDING PAPER STOCK TO A PAPER MACHINE Erik A. Nykopp, Tampere, Finland, assignor to y Tampella AB, Tampere, Finland Filed Jan. 17, 1969, Ser. No. 791,937 Claims priority, application Finland, Mar. 26, 1968, 836/68 Int. Cl. D21f 1/06 US. Cl. 162343 9 Claims ABSTRACT OF THE DISCLOSURE An apparatus for feeding paper stock to a paper machine in which even distribution of the pulp stock free from fiber accumulations is obtained across the entire width of the paper machine. The stock flows from distribution tubes into a chamber through a plurality of transverse inlet rows and impinges on the opposite wall of the chamber. The inlet wall is provided with humps which extend across the chamber, both parallel to and between each pair of inlet rows. The stock flows from the chamber through a discharge channel and to the head box of the paper machine.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to an apparatus for feeding paper stock to a paper machine, and more particularly to an apparatus which has a distributing tube system for feeding the pulp stock into a chamber in the apparatus through a plurality of inlets, which are situated in the wall of the chamber, in at least two parallel rows across the apparatus, uniformly spaced.

Description of the prior art Prior known are apparatuses of this type including a chamber and a distributing pipe system for feeding pulp stock into the chamber through inlets situated in the bottom of the chamber. Also prior known is to arrange said inlets in a plurality of parallel rows across the machine, whereat the inlets form a symmetrical pattern, where the lines drawn through the centres of the inlets parallelly and transversally with respect to the rows, form a screen pattern and cross each other at an angle of 90.

Now, however, it has been found out that the mentioned prior known inlet arrangement is not optimal.

SUMMARY OF THE INVENTION The improved apparatus according to the invention offers several advantages compared with the above prior known apparatuses. The most important advantage is that the distribution of the pulp stock is more uniform and contains less fiber accumulations than in the case of feeding pulp stock by means of prior known aparatuses. Another important advantage is that the apparatus according to the invention is more compact and less costly than the prior known apparatuses. The apparatus according to the invention can be utilized both in Fourdrinier machines for feeding paper stock to the head box, which can be a pressurized head box, and in cylinder paper machines for feeding the stock to the cylinders.

The principal characteristics of the apparatus according to this invention are that the said inlets in one row are displaced with respect to the inlets in adjacent rows, and the said wall being between two transversal inlet rows provided with a hump parallel to the said rows.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings FIG. 1 illustrates a preferred embodiment of the apparatus according to the invention, in side 3,591,452 Patented July 6, 1971 elevation and in section. FIG. 2 shows, in greater scale, a section along the lines A-A of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 the distributing tube system is shown at 1. The chamber is shown at 8 and its top wall at 3, while the bottom of the chamber is, in FIGS. 1 and 2, shown at 4. Reference numeral 6 indicates the outlet channel from the chamber and reference numeral 5 in FIGS. 1 and 2 indicates humps removably secured to the chamber bottom, the method and element for securing the humps being shown in FIG. 1 at 7.

In the embodiment shown in FIGS. 1 and 2 the paper stock is fed to the chamber 8 through the distribution tubing 1 and the inlets 2. The inlets 2 are situated at the bottom of the chamber, in three rows, which are parallel and extend in the cross direction of the apparatus spaced from each other. From the chamber 8 the paper stock is directed through the discharge channel 6 into the head box of the paper machine or to a cylinder for the formation of a web.

It is of first-rate importance that the fibers in the pulp stock are not allowed to form accumulations which would make the paper uneven. It is also important that the pulp stock is evenly distributed across the entire width of the paper machine.

According to the present invention, and as shown in the embodiment presented in FIGS. 1 and 2, the inlets 2 situated in one row are displaced with respect to those situated in the other rows and at least those situated in adjacent rows, whereby the pulp stock is distributed very uniformly across the entire width of the apparatus. By virtue of this arrangement the chamber 8 can be relatively small, whereat the stock delivered from the distributing tubes 1 impinges at a high veocity against the top wall 3, so as to be effectively dispersed. The humps 5 eliminate the so-called dead points otherwise appearing in the flow, where the fibers tend to re-accumulate.

As shown in FIG. 1 the bottom of the chamber 8 is made wavy by providing humps 5 between the inlet rows. These humps prevent the re-formation of fiber accumulations in the chamber. At the same time the distance between the chamber bottom 4 and the chamber top wall 3 can be considerably reduced, preferably to be between from to 120 mms., whereby the dispersing effect of the chamber is increased.

It is of importance that the flow conditions in the chamber 8 can be made such that the fibers are not permitted to accumulate. This is achieved by the humps 5 and their appropriate configuration.

The cross section of the humps 5 is preferably in the form of an inclined triangle with a height of between /3 and /2 of the total height of the chamber 8, and the base angles of which are between 25 and 45, preferably 35, and respectively between and 80, preferably The steeper side of the hump faces toward the discharge channel 6 of the chamber and the distance of the hump base angles from their near inlets is not more than 30 mms. The tubes and inlets 2 of the distributing system I preferably have a diameter from 20 to 45 mms., so that the highest possible flow velocity in the distributing tubes 1 will be less than 10 meters per second, preferagly 7.5 meters per second.

Preferably the humps 5 are removably secured to the bottom 4 of the chamber 8 by means of screws 7 (FIG. 1), but it is to be understood that they can be secured on the bottom of the chamber either fixedly or adjustably when so required.

The number of the inlet rows can be greater than three, but at least two rows must be provided for the invention to be practicable.

Iclaim:

1. Apparatus for feeding paper stock to a paper machine, comprising in combination; a distributing tube system; a chamber having a front wall with a discharge opening for feeding the stock to the paper machine, a rear wall, two side walls, and top and bottom walls one of the two last mentioned walls being provided with a plurality of inlets for delivering the stock from the distributing tube system into the chamber so that the stock impinges against the opposite wall of the chamber, the inlets being arranged evenly spaced from each other in at least two parallel rows extending transversally across the apparatus and the inlets in one row being displaced with respect to the inlets in adjacent rows; and at least one hump on said one last mentioned wall extending across the apparatus said hump placed parallel to and between each pair of transverse rows of inlets.

2. Apparatus according to claim 1, wherein the inlets in one row are displaced with respect to all other inlets.

3. Apparatus according to claim 2, wherein the inlets and said hump are at the bottom wall of said chamber.

4. Apparatus according to claim 3, wherein the distance between the base angles of said hump and the adjacent inlets is less than 30 mms.

5. Apparatus according to claim 4, wherein the hump is of a triangular cross section.

6. Apparatus according to claim 5, wherein the cross section of the hump is in the form of an inclined triangle, the steeper side of which faces toward the discharge channel of the said chamber.

7. Apparatus according to claim 6, characterized in that the base angles of said hump are from 25 to degrees and from to degrees, respectively.

8. Apparatus according to claim 7, wherein the height of said hump is from /3 to /2 of the total height of said chamber, and the distance between the bottom wall and top wall of said chamber being from 50 to mm.

9. Apparatus according to claim 8, wherein the hump is removably secured to said chamber.

References Cited UNITED STATES PATENTS 1,821,198 9/1931 Zimmerman 162343X 3,385,754 5/1968 Burgess, Jr. l62-343X FOREIGN PATENTS 370,422 3/1923 Germany 162343 S. LEON BASHORE, Primary Examiner T. G. SCAVONE, Assistant Examiner U.S. CL. X.R. 162-336 

